1. Prepare Oven and Pan:

• Preheat your oven to 350°F (175°C).
• Lightly butter the bottom of a 9×13-inch baking pan.

2. Make and Bake Pretzel Crust:

• Crush pretzels into coarse crumbs (a food processor works well, or use a sealed bag and rolling pin). Measure out 2½ cups of crumbs.  
• In a medium bowl, combine the 2½ cups crushed pretzels, ¾ cup sugar, and ¾ cup melted unsalted butter. Stir well until all the pretzel crumbs are evenly moistened.
• Press this mixture firmly and evenly into the bottom of the prepared buttered 9×13 pan. Use the bottom of a glass or your fingers to create a packed layer.
• Place the pan in the preheated oven and bake the pretzel base for 10 minutes.  
• Remove the pan from the oven and place it on a wire rack to cool completely to room temperature.

3. Prepare Jell-O Base and Chill Slightly:

• While the crust bakes/cools, prepare the Jell-O. In a medium, heatproof bowl, add the strawberry gelatin powder (6 oz total).
• Carefully pour 2 cups of boiling water over the gelatin powder. Stir continuously for about 2 minutes, or until the gelatin is completely dissolved.
• Stir in 2 cups of ice water (or very cold water). Continue stirring until the ice water is incorporated and the mixture begins to cool down.
• Place this Jell-O mixture in the refrigerator for about 15 minutes (or potentially longer, keep checking). You want it to thicken slightly to the consistency of unbeaten egg whites – just starting to set but still liquid enough to pour and suspend fruit. Do not let it become fully set.

4. Make the Cream Cheese Filling:

• While the crust cools and Jell-O chills slightly, make the filling. Ensure the cream cheese is fully softened and the whipped topping is thawed but cool.
• In a large mixing bowl, beat the softened cream cheese, the remaining ¾ cup of sugar, and the vanilla extract together using an electric mixer (handheld or stand) until the mixture is smooth, creamy, and well combined.
• Gently fold in the thawed whipped topping using a rubber spatula until evenly incorporated and no streaks remain.  

5. Layer Filling on Cooled Crust and Chill:

• Once the pretzel crust is completely cool, carefully spread the prepared cream cheese mixture evenly over the crust.
• Crucial Step: Make sure to spread the cream cheese mixture all the way to the edges of the pan, creating a complete seal over the pretzel crust. This barrier prevents the liquid Jell-O from seeping down and making the crust soggy.
• Place the pan back into the refrigerator and chill for at least 30 minutes to allow the cream cheese layer to firm up slightly.

6. Finish Jell-O Topping and Layer:

• Check the Jell-O mixture in the refrigerator. Once it has thickened slightly (like raw egg whites), remove it.
• Gently stir the sliced fresh strawberries into the slightly thickened Jell-O mixture.
• Carefully pour this strawberry-Jell-O mixture evenly over the chilled cream cheese layer in the pan.

7. Chill Until Fully Set:

• Cover the pan carefully with plastic wrap or foil.
• Place the pan back in the refrigerator and chill for at least 2-3 hours, or until the Jell-O topping is completely set and firm.

8. Serve:

• Once the Jell-O is fully set, cut the Strawberry Pretzel Jello Salad into squares using a sharp knife.  
• Serve chilled and enjoy!